OSMAN1A UNIVERSITY LIBRARY
Call No. 55 \ "M / ,V^ 6, Accession No.
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This book should be returned on or before the date last marked below.
Glacier Variations and Climatic
H. W:SON AHLMANN
THE AMERICAN GEOGRAPHICAL SOCIETY
NEW YORK 1953
BOWMAN MEMORIAL LECTURES
Series One. Geography, Justice, and Politics at the Paris Conference of
1919. By Charles Seymour. 1951
Series Two. Agricultural Origins and Dispersals. By Carl O. Sauer. 1952
American Geographical Society
George Grady Press, New York
THE THIRD in the series of the Isaiah Bowman Memorial
Fund lectures was delivered by His Excellency Hans
W:son Ahlmann on August 13, 1952, as the principal ad-
dress at the meeting of the Seventeenth International Geo-
graphical Congress in Washington, D. C. The original
text of "Glacier Variations and Climatic Fluctuations"
has been augmented for publication by additional data
and references to serve as a summary of the author's latest
thinking on the subject. It brings together the findings
of the human and physical geographer, the geomorphol-
ogist, the climatologist and even the historian. Dr. Ahl-
mann has been Professor of Geography at the University
of Stockholm, and from 1948 to 1951 served as President
of the Commission on Snow and Ice of the International
Association of Hydrology (I.U.G.G.).
Dr. Ahlmann, now serving his country as Sweden's
Ambassador to Norway, has for two decades been the
leader in the work of relating changes in glaciers to
climatic fluctuations. His concept of the need for collabo-
ration between sciences the team approach and the ne-
cessity for initiating detailed observations to achieve a
better understanding of glacier regimen has changed the
whole scope of glaciology. He has pioneered in developing
methods for making precise measurements of accumula-
tion and wastage from which to determine a glacier's econ-
omy or hydrologic balance. These techniques not only
provide means of learning more about glaciers themselves,
but also make possible a much more accurate and satis-
factory interpretation of their response to meteorological
factors and other external influences.
Dr. Ahlmann's studies began in Norway in 1918, were
extended to Spitsbergen in 1931, to Iceland in 1936, and
to northeast Greenland in 1939. The Norwegian-British-
Swedish Antarctic Expedition, 1949-1952, was largely a
product of his planning and organization. In the summer
of 1952, following the meeting in Washington, he made
a brief visit to Southeastern Alaska under the auspices of
the American Geographical Society, supported by funds
generously provided by the Office of Naval Research. His
objective was to observe the principal glaciological fea-
tures of that area and to evaluate the studies being made
there by this Society and others, in order to further the
development of a well-integrated international program
of glaciological-climatological research.
We may appropriately recall the Foreword he wrote in
the first issue of the Journal of Glaciology, January, 1947
(p. 3): "As a science glaciology is young, even though snow,
ice and glaciers have been noticed for centuries . . . but
they have been remarkably late in becoming the subject of
systematic investigation. And this in spite of the fact that
snow and ice are of great practical importance in northern
countries. . . . We are as yet only on the threshold of the
world of ice in the Antarctic that conceals the answer to
questions of the greatest importance to the understanding
of physical-geographical conditions both at the present
time and during the Ice Age. The glaciers at all latitudes
round the earth are of no less interest. As yet we know very
little about the meteorological reasons for their existence
and variations in size, about their structure, movement and
other features. . . . The tasks confronting us are immense
and various ..." In this volume, as in his many other writ-
ings, Dr. Ahlmann clearly points the way to the future
development of glaciology in both its practical and theo-
retical aspects, especially as it may contribute to the study
of climatic change.
W. O. FIELD, JR.
Glacier Variations and Climatic
I REGARD it as a very great honor to have been asked to
give this lecture in memory of Isaiah Bowman, a man
whose attainments as a scientist I have long appreciated
through his writings and whom I had the pleasure to know
personally, not only as a man of great distinction and a
citizen of the United States, but as a citizen of the world.
As the subject of my lecture I have selected a chapter in
climatology. This science is of importance not only to
glaciologists; it affects the whole social and economic life of
mankind. Isaiah Bowman was much interested in climate
and its changes. In studies of the pioneering process, for
instance, he gave full recognition to climate as a critical
element. He often cited the early Norse settlement of
Greenland as an experiment on the "verge of the possible/'
where even a slight climatic change brought disaster. 1 And
he stressed the need of quantitative study. He himself "car-
ried out measurements on physical indications of climatic
change on tree rings and on strandlines in Great Basin
lakes and later he prompted the National Academy of
Sciences to undertake cyclic-change studies in weather and
climate." 2 Glaciers and glaciation were a subject of special
attention in his field work in the Peruvian Andes.
Of recent years, glaciers have been the object of intense
scientific research. That research, moreover, is differenti-
ated by today's cooperation between various scientific dis-
ciplines whereby many new aspects of a more profound
geophysical nature have been opened up. To take one ex-
ample, it is only within the last 20 years that any close
attention has been given to the glacier ice itself. 3 The
earlier unconcern has run through the whole course of
polar exploration; it applies particularly to Antarctica,
with 99 per cent of its area ice covered.
Today we have a better appreciation of the necessity for
more intimate knowledge of present-day glaciers if we are
ever to understand Pleistocene glaciation. Richard Foster
Flint's "Glacial Geology and the Pleistocene Epoch/' pub-
lished in 1947, is one of the first comprehensive works to
use glaciology as a basis for study of this period. His ap-
proach became feasible only as a result of the recent rapid
advance in glacier study.
Our extraordinary technical progress has made it pos-
sible to achieve results in practically all branches of science
that no one would have dreamed of only a few decades ago.
Such, for instance, in the field of polar research, is the
determination by the seismic reflection method of the
depths of the inland ice plateaus of Greenland and Ant-
arctica. In Greenland this has been carried out by the
French Polar Missions of Paul-Emile Victor, 4 and in the
Antarctic by the Norwegian-British-Swedish Expedition
to Queen Maud Land, 1 949- 195 2. 5
SOME PRELIMINARY GLACIOLOGICAL RESULTS
FROM QUEEN MAUD LAND
Figure i, reproduced with the permission of Gordon
Robin of the Queen Maud Land expedition, gives the re-
sult of his seismic depth measurements from 71 S. to 74
30' S. It reveals a wild alpine topography covered with ice
to a depth of up to 2500 meters an immense mass. On the
basis of the French results in Greenland, Andre Cailleux 6
is quite right in saying that previous estimates of the
world's existing glacier ice are too small. He calculates that
the total volume of land ice must be between 26 and 36
million cubic kilometers. Melting of this volume of ice
would raise the sea level by some 65 to 90 meters. Even
after making allowance for isostatic adjustments, the rise
would be from 43 to 60 meters. Now, as a result of the work
in the Antarctic, we can say that the higher figure, 60
meters, is probably a minimum value.
I should like to mention here some other results of
general interest from the Queen Maud Land expedition.
V. Schytt's measurements at Maudheim show that temper-
atures in the inland ice and in the shelf ice below the level
to which the seasonal fluctuations penetrate (below about
20 meters) correspond to the local mean air temperatures.
Thus we have a method of determining this very important
climatological element in a given place on the ice, even
though we can only stay there for a day or two. Near the
southern end of the profile in Figure i, at 2700 meters
above sea level, the average temperature for the year has
been calculated in this manner to be about -40 C. Temp-
eratures below -50 C. must be common in the winter
The possibility of traveling over the Antarctic and the
Greenland icecaps with mechanical snow vehicles may
soon bring us to the day when we shall know the average
air temperature over the inner parts of these regions. Aside
from the value of such information to regional geography,
we can reasonably expect that the results obtained may
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serve as a basis for increased knowledge of the climate on
and around the masses of Pleistocene inland icein other
words, of the climate during the Ice Age. Present-day
knowledge about the great ice sheets of the past is ex-
tremely limited. I am still convinced that at least most
parts of the Pleistocene ice sheets were of polar and not of
temperate type, that is to say their temperatures were be-
low the freezing point to a depth of at least a couple of
hundred meters, with the upper score or more consisting
of frozen snow, firn, not ice. 7 Schytt's geophysical and crys-
tallographic analysis of a loo-meter-long core at Maud-
heim has shown that there was no real glacier ice at lesser
depths than Go meters.
FACTORS INFLUENCING GLACIER VARIATIONS
Glaciers, being conditioned by climatological factors,
register by their variations fluctuations and changes of cli-
mate. Even the present climates of the world are not stable
as was once believed by meteorologists, among them the
great Hann. They are, and always have been, subject to
fluctuations and changes over both long and short periods.
The scope of this field of research is so vast that I must limit
myself to the Scandinavian countries and Iceland, with
some comparisons from North America.
The relations between glaciers and climate are highly
complicated and still far from clear. Until we have solved
the problems of the existence and the variation in size of
glaciers, their structure, movement, and other features, we
cannot fully utilize them as the climatological registers
they really are. Robert Sharp 8 correctly says that accumula-
tion is the life blood of a glacier and that "its state of health
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can best be defined in terms of the relation between accu-
mulation and wastage." Ablation, or wasting (melting and
evaporation), is the crux of the matter. It seems as if abla-
tion is at least as important as accumulation in this appar-
ently simple relation. But it is only recently that attention
has been turned to the question of which meteorological
factors determine ablation in different regions.
The basic work in this subject was carried out in 1934
by H. U. Sverdrup on Isachsen's Plateau, a vast snow-
covered transection glacier in Spitsbergen. 9 It was con-
tinued on the Karsa Glacier, a small cirque or valley glacier
in Swedish Lapland, by C. C. Wallen in 1942-1 948. 10 From
Wallen's recent review of the most conclusive results," the
following can be summarized. The relative importance of
the climatic elements determining the "health of the gla-
cier" varies from one region to another. As a rule we have
to take into account: ( i ) the amount of the annual precipi-
tation in solid form; (2) the temperature during that
period of the year when it is above the melting point; (3)
the length of that period; (4) the amount of incoming and
outgoing radiation, both being influenced by the degree
of cloudiness; (5) the wind velocity; (6) the humidity.
The relative importance of the different factors gradu-
ally changes from the beginning of the ablation season to
its end. The influence of radiation diminishes from early
July onwards. Its effect also depends on the nature of the
surface, whether snow or ice, for ice has a smaller albedo
In spite of differences in latitude and local conditions,
the most important factors in the ablation process are
shown to be convection (heat received from the air) and
radiation. Condensation plays a much smaller part, evapo-
ration a still lesser. It seems that the importance of radia-
tion increases with decreasing latitude. Table I is repro-
duced from Wallen's report.
The more maritime and humid the climate the more
important in the process is convection. Vatnajokull in Ice-
land is a good example of a glacier where ablation takes
place under these conditions and where convection plays
a much more important part than radiation. 12 On the other
hand, in Peary Land in northernmost Greenland, where
the climate is extremely continental and arid, evaporation
from the icecap is the most important factor in the ablation
Our present knowledge of glacier variations is mainly
based on observations of their size and especially of their
marginal variation. But the variations are primarily a con-
sequence of the thickening and thinning of glaciers, in
other words, of changes in volume.
These latter changes are far more difficult and trouble-
some to determine than the oscillations of the termini.
Here an important question is: When does a glacier front
react and, by advancing or retreating, affect its "health"?
A small glacier will naturally react sooner than a large one.
The rate of reaction is dependent also on the topography.
If the gradient is steep or the depth great the glacier will
move rapidly and the changes will be transmitted to the
terminus more quickly than if the slope is gentle or the
thickness small. Advances and retreats will therefore
usually begin and end at different times, even in the same
region. There is also a difference between glaciers termina-
ting on land and in water, especially if the glacier tongue
is afloat. The importance of calving is to be considered and
the fact that the rate of movement of the glacier increases
towards the ice cliff. 14
In the polar regions we must distinguish between the
main inland ice masses on the one hand and on the other
their outlet glaciers and local glaciers of different types.
Because of the very great area of the inland ice in the
Antarctic and in Greenland it is difficult to obtain measure-
ments that are either representative or accurate enough to
lead to any certain conclusion about the ice regime; that
is to say, whether the total volume is increasing or decreas-
ing. The Antarctic inland ice is largely surrounded by
floating shelf ice, the extension of which is dependent on
other factors than those of climate and glacial regime alone.
In relation to the whole Antarctic inland ice and the main
body of the Greenland inland ice, we must also bear in
mind that the reaction to changes of climate is very slow.
The Antarctic "cold center" especially offers strong re-
sistance to external forces. In both these parts of the world
the summer temperature is so low that a rise of a few de-
grees may not bring the temperature above the melting
point, and thus affect the ablation. Variations in the posi-
tions of the termini of outlet glaciers from inland-ice
masses are related to the supply of ice as it was determined
by climatic conditions of a long time before.
In a short preliminary review of the scientific work of
the Norwegian-British-Swedish Expedition, E. F. Roots 15
points out that "the lag between climatic change and
change in form of the glacier may be longer than the period
of climatic change itself " and that the Antarctic icecap is
one great accumulation area. He adds: "A further possi-
bility is that the thickness of the Antarctic ice-cap is not
dependent on climatic conditions at all, provided there is
sufficient snow accumulation to develop an equilibrium
cross-section determined by the physical properties of ice
and the resistance offered by the rock floor."
In recent years we have gained knowledge of some
special types of high-polar glaciers. The icecaps in Peary
Land, where evaporation is predominant among the causes
of ablation, are characterized by Fristrup as masses of dead
ice, which have possibly grown up under conditions of
much greater annual accumulation and surplus in the
regime than is the case under present conditions. The
outlet glaciers of the inland ice are of a different type; they
move fast and transport large quantities of ice. Glacier caps
very similar to those found in the interior of Peary Land
occur on Baffin, Bylot, and Devon Islands, and the south-
ern part of Ellesmere Island. They have been described by
Baird, 16 and are classified by him as the "Baffin Type/'
Their nourishment is not by accumulation of firn but by
superimposed ice from the immediate refreezing of sum-
mer melt water. Baird has the same impression as Fristrup,
namely that these glacier caps are relics from a climatic
epoch of the past, one that was neither so cold nor so arid
as the present.
The following statement by F. E. Matthes 17 on the laws
of ice flow is further of great importance: "Ice confined in
a reservoir remains inert under steadily increasing pressure
until a certain point is reached when flow sets in slowly at
first, but increasing rapidly in velocity, even though the
pressure remains constant or is diminished. The flow then
continues with gradually diminishing velocity until the
reservoir is well depleted, when the ice-mass returns to its
inert state. The annual overflow from a glacier cirque does
not correspond to the annual accretions; but the snow
keeps on accumulating for several years as a rule, until
sufficient pressure is reached to inaugurate a strong and
rapidly accelerated forward movement. A conspicuous
advance of the glacier front results, which does not stop
until the cirque is drained to a lower level/*
In a lecture to the Norwegian Polar Club, Oslo, early
in 1952, O. Liestol expressed the same opinion. Glaciers
have a tendency to establish time variations of their own
that are more or less independent of climatic factors. Over
a long period of time a surplus may be built up in the
accumulation area, while the lower part of the glacier con-
currently wastes away until the frictional limit is exceeded,
and the ice slides forward. Such a condition, he says, is
most evident in polar and subpolar glaciers and, it may
also be added, is especially applicable to glaciers whose ac-
cumulation areas are situated on plateaus high above the
valleys constituting their main ablation areas. Such are the
Spitsbergen glaciers, which, moreover, mostly terminate
in floating tongues in fiords.
For the great majority of glaciers there is obviously a
greater or lesser time lag between the beginning of a clima-
tic fluctuation and the ensuing marginal variations. Hence
it is very unlikely that variations in length of a glacier are
strictly comparable with short climatic fluctuations, as, for
example, an ii-year sun-spot period. The reactions of
different glaciers to climatic fluctuations extending over
considerable periods several decades or centuries may,
on the other hand, reach their climax at about the same
time, provided that the physical structures and morpholo-
gy of the glaciers are not too different.
GLACIER REGIME IN SWEDISH LAPLAND, 1941-1952
For diagnosis of the "health of a glacier" Wallen from
1941 to 1948 carried out systematic studies on the small
Karsa Glacier (2 sq. km.; see PL I A). Since 1946 similar
but more detailed investigations have been carried out by
Schytt and Woxnerud on the Stor Glacier (3.3 sq. km.; see
PL IB) on the highest mountain range of Sweden, Kebnek-
TABLE II REGIME OF THE KARSA AND STOR GLACIERS
Kdrsa Glacier (68 zo'N., 18 2o'E.; alt. 820-1440 m.)
Def. ( ) or Def. or Sur.
Sur. ( + ) per km. 2
Alt. of Retreat
Firn Line of Front
meters of water
Stor Glacier (6y^o'N. f i8^o'E.; alt. 1080-1700 m.)
ajse. 18 The glacier regime, or material balance, is deter-
mined for each "budget" year. A budget year begins in
the autumn, when the accumulation first exceeds ablation
at the firn limit; it thus extends from the first snow fall
of winter through the ablation season of the following
summer. 19 By regime is meant the total accumulation vol-
ume through one accumulation season minus the net
ablation during the following melting season, expressed
in terms of water.
Preliminary results from the Lapland projects are
shown in Table II. The values for the Stor Glacier are
based on about 10,000 measurements.
Total accumulation and ablation have varied consider-
ably from one year to another. On the Karsa Glacier the
balance between them was negative three years, positive
one year (1947-48), and balanced in one (1943-44). The
sum total for the five budget years shows a net deficit of
2.2 million cubic meters of water, or o.i million a square
kilometer a year. The corresponding figures for the Stor
Glacier were five years with negative regime, one with
positive and one with balanced; the total deficit for these
seven years was 12.1 million cubic meters or 0.5 a square
kilometer a year.
The retreat of the termini of both glaciers was con-
tinuous and proportional to the regime. The regime of the
Stor Glacier, it may be added, is representative of the 16
small glaciers lying in the same massif. The highest peak of
the Kebnekajse Range is covered by a small glacier that
accurate measurement 20 has shown to vary in height with
the regime of the Stor Glacier. In 1950 this highest point
in Sweden was 2117 meters above sea level.
It is important to note that the significance of the air
temperature to the glacier regime is determined in par-
ticular by its variations around freezing point. It makes no
appreciable difference to the majority of temperate glaciers
if the winter is more or less cold, whereas the amount of
melting during the ablation season is of the utmost con-
sequence. High spring and autumn temperatures prolong
the ablation period, high summer temperatures intensify
The negative regime, the thinning, and the retreat of
the Stor Glacier during the seven years in which it has
hitherto been observed, is a continuation of its behavior
during the preceding decades. Since 1908 it has been
characterized by recession; concurrently there has been a
rise in the spring, summer, and especially autumn tem-
peratures in Lapland.
THE RECENT GLACIER RECESSION
Most glaciers in both northern and southern hemis-
pheres are known to have been receding more or less
rapidly for several decades. This, "the recent glacier re-
cession/' is exemplified by the curves (Fig. 2) showing the
variations of glacier termini in some of the best known
areas: Scandinavia, 21 Iceland, 22 the Alps, 23 and parts of
North America. 24 Large glaciers have become smaller (PL
II), small ones have disappeared completely or have be-
come dead ice.
I will mention some few examples from the Arctic. Most
of the outlet glaciers of the Greenland inland ice have been
in recession for several decades. 25 Froya Glacier (74 24'
N., 20 50' W.) on Clavering Island in northeast Green-
land, a local glacier with well-defined boundaries, was in-
Maximum extension end of 17th Century
Maximum extension about 1910
1675 1700 1725 1750 1775 1800 1825 1850 1875 1900 1925 1950
1725 1750 1775 1800 1825 1850 1875 1900 1925 1950
1725 1750 1775 1800 1825 1850 1875 1WO 1925 1950
ICELAND, DRANGAJOKULL, 66N.
ICELAND, VATNAJOKULL, 64N,
1750/51 1800/01 1850/51 1900/01 1950/51
SAVOIE, THE ALPS, 45N.
(M. Mougin, 0. Liestol)
1600 1625 1650 1675 1700 1725 1750 1775 1800 1825 1850 1875 1900 1925 1950
BRITISH COLUMBI A, 50N. ' ^
(Mt. Garibaldi area, W. H. Mathews) S. E. ALASKA, 60N.
1700 1725 1750 1775 1800 1825 1850 1875 1900 1925 1950
FIG. 2 Curves showing the variations of glacier termini. For details on construction of
the curves see footnotes 21, 22, 23, and 24.
vestigated in 1939-1940, the position of the snout was
measured again in 1947 and in 1952. 26 It has continuously
receded in a manner which may be said to be representa-
tive of the recent glacier behavior in that part of the Arctic.
'; ' " +385 *s^_-
^;;c^^, Terminal moraine
---- Glacier Terminus 1939
^^J Glacier Terminus 1952
150+ Meters above sea level
FIG. 3 The snout of Froya Glacier, Northeast Greenland (74 24'N.), in 1952.
with terminal moraines indicating its maximum extension, probably in about
1750. The dashed line is the terminus in 1939.
On the basis of sketch maps and photographs taken in these
years Swithinbank concludes that the snout had receded
75 meters between 1939 and 1947 and a further 50 meters
up to 1952 (Fig. 3); this retreat, however, represented a
decrease of only about 2 per cent in the total area of the
glacier. There was a corresponding thinning of the ice even
at altitudes well above that of the snout; for instance, at
450 meters above sea level the glacier surface in 1952 was
about 15 meters lower than in 1939. The active bulging
tongue that formed the snout when the older photographs
were taken had completely disappeared by 1952, leaving
only a smooth, partly moraine-covered front of a type more
characteristic of a dead ice mass.
The Chr. Erichsen Glacier, a special high-polar type in
Peary Land investigated by the Danish Expedition, 1947-
1 950, and described by Fristrup, had a negative regime and
was receding. A great part of the tableland around the
glacier gives the impression of having been only recently
laid bare. The Barnes Ice Cap on Baffin Island 27 showed
a small deficit for the budget year 1949-1950, that year not
being greatly different from the normal during the previ-
ous decade. Photographs taken in 1934 and in 1950 show
only a barely perceptible thinning in its lower section.
It has already been mentioned that in Spitsbergen con-
ditions are in many respects peculiar. A summary prepared
for me by Liestol, points out that glacier snouts that have
receded over a hundred years or so, suddenly begin a rapid
advance, sometimes reaching as far as the outermost recent
terminal moraines. Every glacier has its own period of
variation, which is, however, dependent on the more pro-
nounced climatic fluctuations and changes. Measurement
of the position of the glacier terminus alone cannot give
satisfactory knowledge of the relation between its varia-
tions and the climate. It is necessary to investigate the
whole glacier. The Finsterwalder Glacier in Van Keulen
Fiord, Bell Sound, West Spitsbergen, has recently been the
subject of comprehensive studies of the kind needed. In
the district south of Bell Sound the total volume of ice
in the glaciers was more or less unchanged from 1920 to
1936. The Finsterwalder Glacier itself decreased in vol-
ume between 1936 and 1950 and showed a strong negative
budget in 1950-1952, mainly because of exceptionally
Thorarinsson's map (Fig. 4) of two glaciers in southern
Iceland, Breidamerkurjokull and Hrutarjokull, supple-
ments the curve showing the oscillations of Icelandic
glaciers (Fig. zD). The present position of the termini
should be about the same as it was in the last part of the
FIG. 4 The termini of Breidarmerkurjokull and Hrutarjokull in southern
Iceland. The glacier front in 1904 (continuous line) is according to the Danish
General Staff; position in about 1850-1890 (dotted line) is based upon the
terminal moraines; position in 1950 (dashed line) is according to a survey by
the Durham University Iceland Expedition.
i7th century; they are much more advanced than in the
time of the Sagas (A.D. 870- 1 2 64) , 28
Before turning to North America the recent general re-
cession of European glaciers may be noted in summary. A
list of measured glaciers for 1 947-5 o 29 shows the following
per cent in retreat in 1947-1948: French, 100; Swiss, 77;
Italian, 98; Austrian, 89; Swedish and Norwegian, 97; Ice-
landic, 88. In total, of 262 measured glaciers 88 per cent
were in retreat, only 6.5 per cent advancing. For 1949-
1950 the figures are: French, 93; Swiss, 99; Italian, 96;
Austrian, 100; Swedish and Norwegian, 91; Icelandic, 67.
In total, of 318 measured glaciers, 96 per cent were in re-
treat, 3.5 per cent advancing, 0.5 stationary.
Our knowledge of the oscillations of the North Ameri-
can glaciers 30 rests partly on old descriptions and photo-
graphs and on tree-ring studies and partly on systematic
measurements. Conditions in different regions sometimes
differ greatly because of morphological and other causes,
as I have already mentioned. Moreover a large number of
glaciers in Alaska end in fiords and are thus in the same
class as the Spitsbergen glaciers with their anomalous
Reference should be made here to two important sys-
tematic investigations the Arctic Institute of North
America's project "Snow Cornice," located on the Seward-
Malaspina Glacier System on both sides of the interna-
tional boundary line in the St. Elias Mountains, and the
Juneau Ice Field Research Project of the American Geo-
graphical Society, supported by the Office of Naval Re-
search. Both have as a common object to help in putting
American glaciology on a dynamic and qualitative base.
On the general situation D. B. Lawrence has this to
say: 31 "The glaciers emanating from the southern part of
the Juneau Ice Field . . . seem to have advanced in unison
to a maximum some time in the early or middle eighteenth
century, which surely had not been exceeded since before
the 1 300% and from which recessions of 1.3 to 5 miles be-
ginning by 1765 at the latest subsequently occurred. The
same chronology has been reported from Glacier Bay,
Alaska, from Garibaldi Park, British Columbia, from Mt.
Hood, Oregon, and even from Norway and Iceland/'
In Alaska the behavior of the glaciers has been more
heterogeneous than in most other parts of the world. 32 As
Matthes earlier pointed out "in a region of such marked
topographical diversity as Alaska, it is to be expected that
some glacier basins will respond more quickly than others,
and on a different scale, to a given change in climatic con-
ditions/' Concerning the immense recession in Glacier
Bay over 60 miles since the i8th century, of which 16
have been since 1892 I am of the opinion that the most
noteworthy fact is the advance of the glaciers in the eight-
eenth century rather than the recession which followed.
The climate in the lower parts of Glacier Bay district,
where the ice has thinned out and from which it has re-
treated, is not suited to the survival of great ice masses.
Even during a climate more favorable to glaciers than that
of the present time, ice transported to the lower parts of
the region must melt away more or less rapidly. The prob-
lem to be solved is the reason for the catastrophic advance
of the glaciers which covered these areas with such a thick
sheet of ice. The recession in Glacier Bay cannot be taken
as evidence of the importance of the present climatic
fluctuation. On the other hand, the glacier advance in the
eighteenth century points towards the probability of there
having been a climate favorable for glaciers during the
preceding centuries. The present advance of Taku, while
all other outlet glaciers of the Juneau Ice Field are reced-
ing, has attracted attention. Perhaps Matthes' claim of "an
upward shift of the zone of maximum snowfall" has actu-
ally taken place in some sections of Alaska. 33
A summary, prepared for me by William O. Field, Jr.
in the spring of 1 952, gives glacier variations in recent years
in that part of North America lying south of Alaska. It
makes clear that the rate of recession of several glaciers has
decreased appreciably, or has even changed to an advance
paralleled by a thickening of the ice. The turning point
in some cases occurred about 1945.^ The renewed activity
of these glaciers has been intensified rather than dimi-
nished during the last two seasons (1951 and 1 952) in spite
of their exceptional melting. The behavior of Nisqually
Glacier and the other glaciers of the same type is dependent
on the relation between snow and ice sources in their upper
parts and the melting of their lower parts. 35
Even if the times of maximum glacier extension in dif-
ferent parts of the world have differed slightly, there is a
striking resemblance in the general trend of variations in
Europe and North America. Comparing the results of
budget studies in Lapland and Alaska we find a close paral-
lel in glacier behavior and temperature development. The
19481949 budget year, which had a strongly positive
regime, was clearly marked in both. The size and com-
position of the accumulation area on the Seward Glacier
also gives evidence of a close parallel in other years.
And though the data from other parts of the world is
less complete, there are nevertheless signs that the margin-
al variations of glaciers have been more or less concurrent
in recent centuries all over the world. 36 The ice fields on
the large extinct volcanoes of Central Africa have dimin-
ished greatly. 37 Old terminal moraines in front of the
present glaciers show that they have been much larger in
relatively recent times. From the post-glacial maximum
extension their retreat appears to have been interrupted
by periods of stagnation and advance. The recession of
some was greater after 1 930 than it was in the period 1 900-
1930. At present, however, the Ruwenzori glaciers seem to
be in a rather stable condition; accumulation normally ex-
ceeds ablation, keeping them well nourished.
More or less definite glacier retreats have been reported
from Asia Minor, 38 South America (especially Chile 39 ), and
also from New Zealand. 40 From the Antarctic we have
Schytt's observations from Queen Maud Land in 1950-
1951. They indicate that at present a state of equilibrium
exists between nourishment and outflow of the inland ice,
and that the ice cover has not thinned during the last
THE PRESENT CLIMATIC FLUCTUATION
As to the present climatic fluctuation, I should like first
to refer to some comprehensive studies, in particular to
Leo Lysgaard's "Recent Climatic Fluctuations*' and H. C.
Willett's "Temperature Trends of the Past Century." 41
The numerical values on Figure 5 are in tenths of a degree
Fahrenheit for the last 20 years, winter temperature
change centered to 1930. It is of particular interest to note
that the temperature rise has been most pronounced in
the northern hemisphere, where it increased with the
latitude, the rise reaching its maximum values in Spits-
bergen (Fig. 6) and in Greenland. No counterpart is in-
dicated in the higher latitudes of the southern hemisphere.
We must remember, however, how scattered and tempo-
rary the observations have been and still are in the Ant-
arctic. Speaking generally, the difference between the sum-
FIG. 5 Twenty-year changes of the mean winter temperatures centered on
1930. The numeric values in tenths of a F. (After H. C. Willett, see footnote 41).
Overlapping 10 years anomalies
from mean value 1901-1930
Fir,. 6 Seasonal mean temperatures in West Spitsbergen (78 N.). Overlap-
ping lo-year anomalies from the mean value 1901-30.
FIG. 7 Seasonal temperatures at Swedish stations plotted in
lo-year overlapping means: Stockholm (59 so'N.); Lund (55
4o'N.); Karesuando (68 2o'N.).
mer and winter temperatures became smaller up to the
1930*8, or in other words, up to that time the climate had
shown a definite tendency to become more maritime.
This is fully confirmed by the curves published by the
late A. Labrijn 42 showing the difference between the mean
temperature of July and that of the preceding January, in
14 places throughout Europe, for the period from 1750
until 1945. The same trend was clearly marked in Lenin-
grad, Stockholm, Edinburgh, and Lancashire (England).
Since the 1930*8 however, it has been reversed. It is worth
noting that Paris, Prague, Vienna, and Budapest do not
show a parallel tendency before the 1930*5 but since that
time the reversed trend (i.e. towards a more continental
climate) has been prominent. Moreover, most other places,
and even subpolar regions, provide evidence that the pre-
sent climatic improvement culminated during the 1930*5
Curves giving ten-year overlapping mean temperatures
from several stations in Sweden (Fig. 7) show that the in-
crease in winter temperatures ceased with the 1930'$ and
was succeeded by an equally clear decrease. At some sta-
tions the January temperatures in the latest decade are
lower than they have been at any time since the turn of
the century. In Stockholm they have not been lower since
1 860. Of course the remarkably cold winters of 1 940, 1 94 1 ,
and 1942 play an important part in this decrease; yet even
if overlapping means are calculated on the assumption that
those winters had normal temperatures, a definite decrease
However, spring and even more autumn temperatures
are still rising. In some parts of Sweden summer tempera^
tures also are rising, in other parts the maxinpiin has al-
ready been reached. It is particularly evident that the rise
of summer temperatures in the glacier regions of north-
western Scandinavia has culminated. At Karesuando and
at Tromso (Fig. 8), for instance, July temperatures show
continuous decrease since 1930-1939. In southern Sweden,
in Lund and Stockholm for example, the maximum 'was
reached only a few years ago or has not yet been reached.
The annual mean temperature is still showing a rising
FIG. 8 Seasonal tem-
perature anomalies from ^ Q
the 1901-30 mean value
at Tromso, Norway (66 gg
On the right lo-year 0.4
below, 3o-year overlap- Q
ping anomalies. Notice
the great difference be-- 0.4-
tween the two groups of
curves. 0-8 -
1899-1908 1909-1918 1919-1928 1929-1938 1939-1946
1856-1885 1866-1895 1876-1905 1876-1915 1896-1925 1906-1935 1916-1945
- -* -*
FIGS, g and 10 Overlapping 10-
year temperature anomalies in Ice-
land from the mean value 1901-30.
Figure 9 (left) is for Reykjavik. (64 10' N.); Figure 10 (right) is for Grimscy
(66 30' N.).
At Reykjavik in Iceland (Fig. 9) the climatic improve-
ment culminated in the 1 940*5 and was succeeded by a
deterioration, particularly in spring and autumn tempera-
tures. But winter and average annual temperatures are
still much higher than they were in the years preceding
1925-1930. The high temperatures recorded since 1890-
1900 in all seasons at Grimsey on the north coast (Fig. 10)
are still being maintained.
In the United States the decade 1 94 1-1 950 seems to have
been characterized by lower temperature and increased
precipitation in comparison with the decade 1931-194O. 43
From many points of view both scientific and practical
it is thus of great importance that we should follow, care-
fully and systematically, the climatic developments of the
near future. This applies especially to the polar and sub-
CAUSES OF THE RECENT GLACIER RECESSION AND
THE PRESENT CLIMATIC FLUCTUATION
The coincidence in time of the recent glacier recession
and the present climatic fluctuation suggests a causal con-
nection between them. I have come to the conclusion that
increased ablation, consequent upon the increase in tem-
perature, has played the fundamental role in the recession
of glaciers around the northernmost Atlantic. I also find
it probable that the rise in spring and autumn tempera-
tures, i. e. the lengthening of the ablation season, has been
of particular importance. As I have said before, 44 "The
great shrinkage and recession of the glaciers is to a pre-
ponderating extent due to an increased transfer of heat
through the atmosphere by a strengthening of the winds
carrying heat from southern parts to the Arctic." The dis-
cussion about the meteorological causes of the present cli-
matic fluctuation that is still going on has for the most part
supported this general thesis.
Twenty-five years ago Wagner explained the current
climatic fluctuation by increased general atmospheric
circulation with an increased exchange of heat and other
atmospheric elements between northerly and southerly
latitudes. 45 More recently B. E. Eriksson 46 found the most
important feature of this fluctuation over the northern-
most Atlantic to be a change in the pressure gradient
causing an increased flow of warm air into northern lati-
tudes. Willett 47 introduced the terms "high-index" and
"low-index" to characterize two quite different types of
circulation in the middle latitudes. With the "high-index"
circulation cyclones move in winter in a strong zonal flow
on fairly northern tracks from the Atlantic towards north-
western Europe giving mild southwesterly to westerly
winds. The "low-index" circulation is characterized by a
meridional flow pattern with the winter cyclonic tracks
shifted southward giving cold easterly and northeasterly
winds over most of Europe. However, Petterssen 48 has
shown that "a warming up of northern latitudes in winter
during the 1930*5 has been connected with a development
towards another type of 'low-index' circulation pattern
where the zonal components are also weak and the north-
south components dominate." Instead of an increased zonal
flow over northwestern Europe there has been a more
meridional type of flow pattern giving rise to an increase
in the northward transport of air from southern and east-
ern Central Europe towards Scandinavia; and simultane-
ously an increased northward transport of air from the
eastern Atlantic towards Iceland and the Norwegian Sea.
Partly in contradistinction to my own opinion is Wal-
len's belief' 9 that the most important cause of the retreat
of the Karsa Glacier during the last decades and probably
of other glaciers in Scandinavia has been the rise of the
summer temperature, 50 with prolongation of the ablation
season of secondary importance. Wallen says: 51 "The es-
sential cause for the regression and shrinkage in recent
decades has been the increase for the heat supply from the
air conveyed by convectional, conductional and conden-
sational processes . . . there has also been a definite rise in
the moisture content of the air ... and it is likely that
the average wind-velocity has increased." In an article in
preparation Wallen shows that the increase of southerly
winds towards northern Scandinavia and the Arctic during
the last 40 years is true not only for winter, as Petterssen
pointed out, but also for summer. Referring to Petterssen's
interpretation he concludes: "The increased general circu-
lation in recent decades has given rise to an increased ex-
change of air between north and south over the Atlantic-
European sector of the hemisphere. Both in winter and
summer there has been an increased frequency of winds
with a southerly component with a corresponding increase
in temperature, humidity and cloudiness but giving no
appreciable increase in winter precipitation."
The "blocking-action" over western Europe 52 which has
occurred quite often during recent decades and which has
given rise to warm southerly and southwesterly winds over
Scandinavia may well have contributed to glacier retreat.
The opinion seems to be gaining ground among meteor-
ologists that both brief fluctuations and long-range changes
of climate, including the Pleistocene glaciations, are of the
same general character and are ultimately dependent upon
solar variations. In an article on the general circulation of
the atmosphere Petterssen 53 points out "that the radiative
processes, in tending to establish radiative equilibrium,
create dynamic instability which gives rise to meridional
circulations that contribute to the exchange of heat and
atmospheric properties." He emphasizes the importance
of mountain ranges, inland water bodies, etc. in the forma-
tion of local circulation systems. A large-scale statistical
analysis of the behavior patterns of cyclones and anti-
cyclones in the northern hemisphere during the period
1 899- 1939 shows agreement between his theoretical re-
sults and existing conditions, thereby giving scientific sup-
port to the old ideas of the importance of mountain chains
and orographically active epochs to the climate in past
Petterssen's circulation models for the lower part of the
troposphere in the northern hemisphere reveal an even
greater similarity in the dynamic-meteorological and
climatological character between Alaska and western
Scandinavia than has been presumed earlier. D. E. Martin,
in an unpublished communication, confirms this by show-
ing that positive and negative anomalies of the 700 milli-
bar surface over Scandinavia are more directly related to
similar anomalies in the Alaskan-Aleutian region than
they are to anomalies elsewhere.
Willett in his study of temperature trends has gone a
step further. He maintains that changes in the ultraviolet
part of the solar spectrum are not only causing the present
climatic fluctuation but have also caused the great and
small climatic changes of the past. Time will show whether
his theory survives better than its predecessors. His idea
has the advantage over most others in that the ultraviolet
solar radiation varies more than the total radiation of
energy. According to Willett, the present amelioration of
the climate has now come to an end, and the temperature
will fall for the next i o or 15 years, reaching a minimum
between 1960 and 1965.
Whatever the future may bring, we are justified in say-
ing that of the endless series of climatic fluctuations that
have occurred from the beginning of the earth and that
will continue in the future, the present one is the first that
we can measure, investigate, and possibly explain.
CHANGES IN ARCTIC DRIFT ICE AND IN ANIMAL
AND PLANT LIFE
The thickness of the ice forming annually in the North
Polar Sea has diminished from an average of 365 centi-
meters at the time of Nansen's Fram expedition of 1893-
96 to 218 centimeters during the drift of the Russian
icebreaker Sedov in 1937-40. The extent of drift ice in
Arctic waters has also diminished considerably in the last
decades. According to information received in theU.S.S.R.
in 1945, the area of drift ice in the Russian sector of the
Arctic was reduced by no less than 1,000,000 square kilo-
meters between 1924 and 1944. The shipping season in
West Spitsbergen has lengthened from three months at the
beginning of this century to about seven months at the
beginning of the 1940'$. The Northern Sea Route, the
North-East Passage, could never have been put into regular
usage if the ice conditions in recent years had been as
difficult as they were during the first decades of this
The same influences that have affected the drift ice have
affected the animal life of the North Polar Sea. Various
kinds of fish, especially cod, have migrated northwards.
Now for the first time cod is available to many Greenland
Eskimos who previously had to rely on seal for food. 55 In
a speech five years ago the Danish Prime Minister said:
"In the last generation changes that have had a decisive
influence on all social life have occurred in Greenland. A
new era has begun. These changes are primarily due to
two circumstances. Firstly, the Greenland climate has
changed, and with it Greenland's natural and economic
On the other hand, herring catches off the north coast of
Iceland have greatly diminished in the last seven years,
possibly because of changes in the sea currents connected
with the present climatic fluctuation. Herring has become
an open sea fishery; its 1952 season was extended to No-
vember instead of ending as usual in August.
It is such phenomena that caused the International
Council for the Exploration of the Sea to adopt the follow-
ing resolution at its meeting in Denmark in 1948: "Having
considered a number of lectures on climatic fluctuations,
the Council recommends that these important and far-
reaching problems ought to be more closely investigated,
and that these investigations might be adequately sup-
ported by the Governments in the different countries." 57
Many land animals in northern Europe and Asia are
now ranging farther north than before. The migration
seems to have begun slowly at the end of the eighteenth
century, but has been greatly accelerated since 1910. Birds
in particular have reacted quickly and markedly to the
present climatic fluctuation. According to a report I have
recently received from C. Edelstam of Stockholm, careful
observation shows that about 25 per cent of all North-
European bird species have taken part in this movement.
The causes are two-fold: throughout the northern regions
winters have been milder and springs warmer. At the same
time lakes and bird-feeding grounds in large parts of Africa
and southwest Asia have dried up. As a result, southern
species dependent on shallow eutrophic waters are strongly
represented in the migration.
Effects of the present climate fluctuation are seen to
advantage in Finland, a country of marginal location. On
the initiative of I. Hustich, the Geographical Society of
Finland has just published a symposium on the phenome-
na, 58 studied from a biological and biogeographical point
of view and embracing effects on forestry, agriculture, fish-
ing, and hunting.
In the first place, it has been observed that the freezing
period in the Baltic decreased during the 1 20 years before
the 1930*8, after which a return to a longer freezing period
began. This later climatic deterioration culminated in the
beginning of the 1 940*5. Since then there has been a rise
in winter temperature, resulting in a longer navigation
Floristically there has been a distinct shift towards
earlier flowering and earlier ripening of berries and other
seeds, and towards later defoliation. Ranges of plants and
trees have expanded northwards, with attendant disturb-
ance of species equilibrium in the plant communities.
Effects on the coniferous forests are of particular in-
terest. Between 1910 and 1920 the average annual ring
index increased in all parts of Finland, especially in north-
ern districts. Analyses of annual rings, which date back over
200 years, show scarcely any other period as favorable as
the 1920*8. The significance of the change in climate, par-
ticularly of the higher temperatures, is even more clearly
indicated by the northern timber line. About 40 years ago
the outlook for the northernmost pine forests was rather
poor, as there had been no seed years there since 1850.
Now, almost all age classes are represented in the seedling
stands (PL III A).
Hustich himself shows the importance of the climatic
factor in the increase in the yield of rye, the commonest
cereal, in the period 1921-1939.
Birds have reacted in the same general manner noted
for northern Europe as a whole. In Finland many species
of mainly northern distribution have become scarcer at
their southern limits, and the accidental species found in
1880-1941 have mainly been newcomers from the south.
Contributions from other countries have been limited
to specialized studies and scattered observations. I think,
however, that in Sweden and Norway the effects may on
the whole be said to be similar to those in Finland. A
critical analysis of the very extensive Swedish material on
annual rings in pine and spruce, though not yet complete,
justifies the statement that the present climatic fluctuation
with its consequent prolongation of the growing season
has probably helped towards the gradually increasing
yield of the Swedish forest, as B. Eklund of the State In-
stitute of Forestry Research has described in correspond-
ence with me.
Changes in the vegetation, as in Finland, are more
marked in the far north, for instance, in the Abisko Na-
tional Park (68 20' N.), undoubtedly because there the
temperature has on the average risen more than in south-
ern Sweden. Peat hummocks containing ice, the so-called
Raises, a typical subpolar phenomenon, have been de-
stroyed by melting of the ice. 60 The timber line for moun-
tain birch has risen about 20 meters during the last decades
and the surrounding vegetation has extended and become
much richer (PL IV), especially during the 1940*5; partly,
it seems, because of the earlier disappearance of the snow
cover and the quicker drying of the soil. Sparse pine stands
that formerly averaged only one new generation a century
have added several new generations since the 1920*5. Dur-
ing the iggo's in particular, regeneration was unusually
An investigation into the water economy of eight catch-
ment areas in various parts of Sweden from 1920 to 1947
shows that evaporation has increased markedly since about
ig 3 o. 61
In most parts of Norway, as in Sweden, the timber line
has risen during the last decades. Among the several causes
are the reduction or discontinuance of lumbering in the
uppermost parts of the birch and coniferous belts and the
reduction of grazing and reindeer keeping. All students of
the problem agree, however, that an improving climate has
played an important part in accentuating the consequences
of such cultural conditions, most especially in northern
In a recent communication, R. Sognen, of the Nor-
wegian Watercourse and Electricity Board, points to an
unfortunate effect that might follow continuance of the
present trend. Continued and rapid recession of glaciers
might prove fatal to some of the Norwegian power genera-
ting stations, for it would reduce the quantity of water
which the ice has stored for centuries and upon which the
stations partly depend for their supply.
The present climatic fluctuation has been even more
marked in Iceland than in the other Nordic countries and
its influence on local plant and animal life is perhaps more
apparent than in any other region. A few of the current and
still continuing changes may be noted: The peat and ice
hummocks, rusts, (same type as the poises of Lapland),
which characterize the marshes, fids, in the interior of Ice-
land (PL III B), are gradually disappearing under the
milder climate. The whole landscape, in fact, is changing. 63
There has been a rise in the lower fid limit; it corresponds
with the northward recession of the southern limit of the
Siberian permafrost zone. In this connection, attention
may also be drawn to the so-called "oriented lakes" 64 of
northernmost North America created by melting of the
Because of Iceland's geographical position, elements of
both southern and arctic faunas live there under peripher-
al conditions and react quickly to climatic changes. Seven
new southern species of birds have begun breeding in Ice-
land within the last 50-60 years, there has been a consider-
able increase in the wintering of partly non-migratory
species, and there has been a very noticeable increase in
winter visitors and vagrants from the south. No less than
37 new species or subspecies of birds have been added to
the Icelandic list since 1938, and at the same time some of
the few arctic and high-arctic species have disappeared. 65
THE PRESENT CHANGE IN THE SEQUENCE
How then do the present climatic fluctuation and the
recent glacier recession compare with conditions in earlier
centuries and millenia? How do they fit into the progres-
sion since the melting of the Pleistocene glaciers?
The two curves of Figure 1 1 are plotted to illustrate our
present conception of the sequence in Sweden 66 and Nor-
way 67 from about 8000 B.C. to 1950 A.D. The glacier-varia-
tion scale is relative and the time scale logarithmic, in order
to show clearly the recent centuries and decades of time,
which are, of course, the best known. The third, dashed
curve, gives the position of the firn or climatic snow line
on Vatnajokull, Iceland, according to Eythorsson. 68
In the lake district of south Sweden, and within the
present coastal region of Norway, the waning inland ice
re-expanded in about 8000 B.C. It subsequently retreated
under the improving climatic conditions. The economic
regime of the Ice Age, which year after year provided a
surplus of snow, had long since been abandoned. The rest
of its immense capital of ice was consumed by a milder
regime, more favorable to mankind. The Climatic Opti-
mum occurred between about 7000 B. C. and about 1000
B. C. In that epoch the firn line of Vatnajokull is estimated
to have been at about 1400 meters above sea level. Studies
xBothnian glacial substage
GLACIER VARIATIONS, SWEDEN
_y ^ v -~-^_
GLACIER VARIATIONS, NORWAY (O. Liestol)
v FIRN LINE, VATNAJOKULL, ICELAND
FIG. 11 The recession of the last Pleistocene inland ice from Sweden
and Norway and the variations of the local Scandinavian glaciers during
the last 12,000 years. For sources see footnotes 66 and 67.
of peat bogs in Sweden have shown that there were prob-
ably changes, in atmospheric humidity at least, in about
2300 and 1200 B.C. The subsequent deterioration of the
climate culminated in about 500 B.C. and the firn line of
Vatnajokull dropped to 500-600 meters. That climate
still exists even if it has improved somewhat during certain
times. There is no evidence in either Sweden or Norway
of any glacier variations or climatic changes during the
following 2000 years, except in the favorable Roman
period (A.D. 0-400). We know, however, as has been
mentioned before that from the first colonization of Ice-
land in A.D. 870 until about A.D. 1200 the glaciers were
much smaller than they are now. The Vatnajokull firn line
is calculated as having been at about 1 100 meters at that
time. From the latter part of the i7th century right up
until the latter part of the i gth and the beginning of the
soth century, glaciers both in Iceland and on the con-
tinent of Europe were more extensive than at any time
since the melting of the last remnants of the Pleistocene
inland ice in the Scandinavian mountains. The Vatna-
jokull firn line dropped to its minimum. The recent gla-
cier recession, which began earlier in some districts and
later in others, has in the last few decades reduced the
glaciers so much that they are now probably as small or
even smaller than they were in Roman time. The Vatna-
jokull firn line has risen successively to its present altitude
of about 1 100 meters above sea level.
Thorarinsson's studies of the past and present cultiva-
tion of cereals in Iceland have shown that in recent years
climate there has been at least as favorable, and probably
even slightly milder than it was in the centuries imme-
diately after A.D. goo, and it is warmer now than at any
time since isoo. 69 According to Thorarinsson, the ampli-
tude of the climatic fluctuation in Iceland has in all proba-
bility been greater since the i88o's than at any time since
about 600 B.C.
It has already been pointed out (p. 18) that the present
position of the termini of some glaciers in southern Ice-
land ought to be about the same as in the last part of the
seventeenth century. They are however much more ad-
vanced than in the time of the Sagas (A.D. 870-1264). The
position of the farms Fjall and Breida (Fig. 4) is not known
exactly but must have been close to that shown. They
were probably built around A.D. 900, and cannot at that
time have been in a dangerous position to a glacier front
or to drainage of ice-dammed lakes. Yet Fjall was aban-
doned in 1695 and buried by the glacier in 1708. Breidd
was a large farm until the fourteenth century, but in 1698
it also was abandoned and in 1702 the glacier front had
almost reached it. Thorarinsson points out that the de-
cline of Breida is not only a result of the deterioration of
the climate but also largely of the eruption of the volcano
Oraefijokull in about 1360. It seems, he says, that this cli-
matic deterioration had already begun in the thirteenth
century, accelerated in the fourteenth, and culminated
during the seventeenth to nineteenth centuries.
These conclusions from Iceland agree with some con-
clusions from Greenland. It is hardly possible that the
climate of southwest Greenland could have been so severe
when the Norse colony there was an independent society
with about 300 farmsteads, 3000 people, and a surprisingly
large number of cattle and sheep, as it was some decades
later. 70 In 1921 excavations of the cemetery at Herjolfsnes
yielded well-preserved clothing from about the year i4oo. 71
Interment must have been in loose earth but preservation
was possible because the ground was frozen soon after the
Concerning the Alps, Kinzl 73 has come to the conclusion
that the glacier advance of the last 300 years is the greatest
that has occurred since the Pleistocene Ice Age. "Those
300 years therefore/' says Matthes, 74 * 'comprise a separate
epoch of glacier expansion, a lesser ice age, that was pre-
ceded by a warm period of considerable duration/' It is
worth while reflecting that our modern machine culture
was born and has grown up under climatic conditions even
more unfavorable, certainly, than those which extended
since Celtic time, i.e., since the Persian wars and Classical
In large areas of North America, as has been mentioned
before, a strong glacier advance attained its maximum in
the first half of the i8th century. It also was the maximum
state of advance since the twelfth century.
Matthes has characterized the period of the last 4000
years as "the little ice age/' I am more inclined to say:
Regeneration of the glaciers began in about 500 B.C.; after
some centuries of rapid increase growth was slower until
the thirteenth or fourteenth centuries when it again accel-
erated and so far has reached its climax in most districts
between the first half of the eighteenth century and about
However, in front of some glaciers, for example some of
Vatnajokull and Myrdalsjokull in Iceland, there are ter-
minal moraines which might indicate that in early "sub-
atlantic" time (the first centuries about the beginning of
our era) these glaciers advanced a little further than during
the last few centuries. 75 In front of several glaciers in the
high mountains of Sweden there also is one morainic ridge
just outside those representing the maximum extension
about 1750 and much older. Similar examples occur in
southern Norway 76 and in the central Alps. 77
SOME ASPECTS OF THE FUTURE
I have tried in this lecture to give you a brief outline of
our present knowledge of recent glacier variations and the
present climatic fluctuation, based chiefly on facts estab-
lished in the Nordic countries and to a lesser extent in
North America. I have also tried to project these phe-
nomena against the background of what Scandinavian stu-
dents consider the most likely progress of the melting of
the inland ice and the most likely local glacier variations
in the last 10,000 years. Our results are most certainly in-
complete and in some, perhaps many, respects may prove
to be erroneous. But in the treatment of these and of many
other problems a new epoch is now opening before us.
A few examples will suffice.
Its new-found geophysical basis has made glaciology bet-
ter able to explain the reactions of glaciers to meteorologi-
cal factors. We hope to be able to organize international
cooperation for the purpose of getting accurate values of
representative glacier regimes for elucidating glaciological-
climatic development in the subarctic zone. The glaciers
ought to be not too big but should be well defined. So far
the following glaciers have been selected: Lemon Creek
Glacier in southern Alaska (near Juneau), a glacier in the
Tindfjallajokull group in southern Iceland, Stor Glacier
in Jotunheim in southern Norway, and Stor Glacier in the
Kebnekajse Massif, northern Swedish Lapland. If possible
we want to include a glacier in northernmost Greenland.
The investigations and measurements are planned to be
of the same kind as those of Stor Glacier in Kebnekajse.
Improved statistical methods of analysis will eventually
provide a more assured and detailed picture of long-range
climatic fluctuations. New methods of age determina-
1*1. I A Karsa Glacier, south ot Abisko Toinisi Station in Swedish Lapland
(68 so'N.). Photo C. C. Walk'n. it)|S.
PI. I B Stor Glacier, Kcbnekajse Massif, Swedish Lapland (675o'N., 2117
meters above sea level). In the background the highest elevation, Sycltopp,
covered by a small glacier. Photo G. Lundquist, August, 1951.
PI. II ABukkho Glacier, Jotunheim, Norway (61 4(>'N.), 19-19. The dotted
line shows the glacier extension in about 1750. Photo O. Liestol, 1919.
PI. II B Engabre Glacier, an outlet glacier from the Svartiscn glacier cap,
Not way (66 [o'), in 1919; in 1930 the glacier still covered most of the lake.
1*1. Ill A Twenty-ihice xear old and \ounger pines in the mountain biuli
forest at Fnontekio in Finland (68 $o'N.). Photo h\ P. Mikola. if) 19.
1*1. Ill 11 A mature pals (tailed rust in hel.md), in a flti soutli ol llofsjokull
Iceland (6.4 <jo'N.); it is (mo in. .ihoM 1 sea lex el. 10 in. long, and neailx ij in.
high. Photo by F. (iudinnnd.s.son, 1*151.
PI. IV A Timber line on
Lapland (68 2o'N.). in 1937;
the eastern slope oi Njulja, Abisko,
) in 19*8. Photo G. Sandberg.
tion, notably by radiocarbon content, will in conjunction
with continued paleobotanical research throw a new and
stronger light on the climatic changes of the past thirty
thousand years. The results of the Swedish Oceanographic
Expedition of 1947-1948 promise to be of great impor-
tance to our understanding of the same phenomena
throughout a much longer period of the world's history.
I have claimed your attention in order to sum up some
of my thoughts on the state of our knowledge of snow, ice,
and climate in selected areas of the world, as well as some
scattered features of changes in the flora and fauna due to
the present climatic fluctuation. I have done so not only
because an account ought to be given of our observations
and results, even though the conclusions may soon be out-
of-date, but also and of greater moment for this gathering
to direct your attention to the many relevant problems,
and to stimulate continued work towards their solution
by the newer and better methods which this constantly
developing science brings forth. For climate, its changes
and fluctuations, is, as Isaiah Bowman has said, a funda-
mental factor in physical geography and one of the most
important influences on the phenomena to which human
geography is devoting its attention.
1 Isaiah Bowman: Geography in the Creative Experiment, Geogr. Rev., Vol. 28,
^S 8 * PP- 1 ~ 1 9-
2 G. M. Wrigley: Isaiah Bowman, Geogr. Rev., Vol. 41, 1951, pp. 7-65.
3 H. W:son Ahlmann: The Contribution of Polar Expeditions to the Science
of Glaciology, Polar Record, Vol. 5, 1949, pp. 324-331.
4 The results of Expeditions Polaires Franchises (Missions Paul-mile
Victor), in Publications preliminaries (mimeographed) and in Resultats sci-
entifiques (Actualit^s scientifiques et industrielles, Hermann et Cie, Paris).
s Popular narratives of the expedition are: John Giaever: Maudhcim: To
ar i Antarktis Oslo, 1952); John Giaever och Valter Schytt: Antarktisboken:
Med Norsel till Maudheim och Antarktis (Stockholm, 1952). English and
American editions will follow. Preliminary scientific reports are: E. F. Roots:
The Norwegian-British-Swedish Expedition 1949-52, Science News, No. 26,
Penguin Books, 1952, pp. 9-32; G. de Q. Robin: Measurements of Ice Thickness
in Dronning Maud Land, Antarctica, Nature, Vol. 171, 1953, pp. 55-58; The
Norwegian-British-Swedish Antarctic Expedition, 1949-52. I. Valter Schytt:
Summary of the Glaciological Work; II. G. de Q. Robin: Summary of Seismic
Shooting Investigations in Dronning Maud Land, Journ. of Glaciol, Vol. 2,
No. 13, 1953, pp. 204-205; 205-213.
6 Quoted in a debate at the Seventeenth International Geographical Congress
in Washington, D. C., August, 1952, in "Premiers Enseignements Glaciologiques
des Expeditions Polaires Franchises 1948-1951."
7 H. W:son Ahlmann: Glaciological Research on the North Atlantic Coasts,
Royal Geogr. Soc. Research Ser. No. i, 1948, reference on pp. 66-67; idem:
The Contribution of Polar Expeditions, op. cit., p. 327.
8 R. P. Sharp: Accumulation and Ablation on the Seward-Malaspina Glacier
System, Canada-Alaska, Bull. Geol. Soc. of America, Vol. 62, 1951, pp. 725-743.
9 H. U. Sverdrup: The Scientific Results of the Norwegian-Swedish Spits-
bergen Expedition in 1934, Part IV, The Ablation on Isachsen's Plateau and
on the Fourteenth of July Glacier in Relation to Radiation and Meteorological
Conditions, Geografiska Annaler, Vol. 17, 1935, pp. 145-166.
10 C. C. Walle*n: Glacial-Meteorological Investigations on the Karsa Glacier
in Swedish Lappland 1942-48, Geografiska Annaler, Vol. 30, 1948, pp. 451-672.
11 Idem: Influences Affecting Glacier Extension in Northern Sweden, Union
Gdodesique et Gdophysique Internationale, Assoc. Internatl. d'Hydrologie Sci.,
Assemble Ge'n. de Bruxelles 1951, Vol. i, Louvam, 1952.
"H. W:son Ahlmann and Sigurdur Thorarinsson: Vatnajokull: Scientific
Results of the Swedish-Icelandic Investigations 1936-37-38, Chapter V, The
Ablation, Geografiska Annaler, Vol. 20, 1938, pp. 171-233 (see also the Geogr.
Rev., Vol. 28, 1938, pp. 412-438); H. W:son Ahlmann: Vatnajokull, Ch. VII,
The Regime of HofFellsjokull, Geografiska Annaler, Vol. 21, 1939, pp. 171-188.
*3 B0rge Fristrup: Climate and Glaciology of Peary Land, North Greenland,
Union Ge'odesique et Geophysique Internationale, Assoc. Internatl. d'Hydro-
logie Sci.j Assemblee Gen. de Bruxelles 1951, Vol. i, Louvain, 1952; idem:
Danish Expedition to Peary Land, 1947-1950, Geogr. Rev., Vol. 42, 1952, pp.
J 4 H. W:son Ahlmann: Scientific Results of the Swedish-Norwegian Arctic
Expedition in the Summer of 1931, Part VIII, Glaciology, Geografiska Annaler,
Vol. 15, 1933, pp. 161-216 and 261-295, reference on pp. 181-186 (Marginal
Movements in the Spitsbergen Glaciers); idem: Scientific Results of the Nor-
wegian-Swedish Spitsbergen Expedition in 1934, Part V, The Fourteenth of
July Glacier, ibid., Vol. 17, 1935, pp. 167-218.
J 5 E. F. Roots, op. cit.
*6p. D. Baird: The Glaciological Studies of the Baffin Island Expedition,
1950, Part I, Method of Nourishment of the Barnes Ice Cap, Journ. of Glacial.,
Vol. 2, No. 11, 1952, pp. 2-9.
!7 F. E. Matthes: Glaciers in Hydrology, Physics of the Earth IX, New York,
1942, pp. 149-219.
18 Scientific Investigations in the Kebnekajse Massif, Swedish Lappland, Parts
I-IV published to date, Geografiska Annaler, Vol. 33, 1951, pp. 90-143. Pre-
liminary reports are: Valter Schytt: Glaciologiska arbeten i Kebnekajse, Ymer,
Vol. 67, i9t7 pp. 18-42; H. Wrson Ahlmann: Kebnekajse, Svenska Turist-
foreningens Arsskrift 7952, Stockholm, 1952, pp. 265-288.
*9 W. O. Field, Jr. and M. M. Miller: The Juneau Ice Field Research Project,
Geogr. Rev., Vol. jo, 1950, pp. 179-190; M. M. Miller and W. O. Field: Explor-
ing the Juneau Ice Cap, Research Reviews, Office of Naval Research, Dcpt. of
the Navy, Washington, D. C., April, 1951; R. P. Sharp, of), cit. Progress Report,
Juneau Ice Field Research Project, Alaska, 1952. Prepared by A. K. Gilkey with
Summaries of Research Work by Members of the Project (mimeographed).
Amor. Gcogr. Soc., January, 1953.
* Erik Woxnerud: Scientific Investigations in the Kebnekajse Massif, Part
IV, Det lokala triangelnatets i Kebnekajse ansluning till riksnatet. Syd- och
Nordtopparnas hojd over havct (The linking up of the local triangulation net
in the Tarfala Valley with the official geodetic net. The heights above sea level
of the Sydtopp and the Nordtopp), Geografiska Annaler, Vol. 33, 1951, pp.
21 The Swedish curve is plotted by E. Bergstrom, Stockholm, on the basis
of his studies in the Swedish glacier districts and of his comparative studies in
Norway. Of great importance to his chronology has been the identification of
three different zones of vegetation cover, which arc represented especially by
lichens. The boundary of each zone appears to correspond to the position of
the ice margin at a time when the glacier extended as far as one of the principal
old terminal moraines.
The Norwegian curve relates to the Nigardsbre, an outlet glacier from
Jostedalsbre, which may be regarded as being representative of the glaciers
of southern Norway. The values are plotted by O. Liestol, of the Norwegian
Polar Institute, from Knut Faegri: Ober die Langenvariationen einiger Glet-
scher des Jostedalsbre und die dadurch bedingtcn Pflanzensukzessionen, Bergens
Museums Arbok 1933, Naturvidenskapelig rekke, No. 7, Bergen, 1934; idem:
On the Variations of Western Norwegian Glaciers During the Last 200 Years,
Procds-Verbaux des seances de I'AssembUe Gen. d'Oslo de I'Union Geodesique
et Geophysique Internationale, Louvain, 1948; and from consecutive measure-
ments carried out by the Norwegian Polar Institute, Oslo.
22 The Drangajokull. curve is based upon Jon Eyth6rsson: On the Variations
of Glaciers in Iceland, I, Drangajokull, Geografiska Annaler, Vol. 17, 1935, pp.
121-136, and for later years on Eythorsson's measurement of four outlet glaciers
from the ice cap, plotted together by Sigurdur Thorarinsson. The Vatnajokull
curve is based upon Eythorsson's measurements of about 18 of the southern
outlet glaciers on the ice cap, summarized to the year 1930, by Thorarinsson in
Vatnajokull, Chapter XI, Oscillations of the Iceland Glaciers in the Last 250
Years, ibid., Vol. 25, 1943, pp. i~54, and after that year supplemented by him.
23 M. Mougin: Glacier des Bossons, tudes glaciologiques en Savoie in tudes
glaciologiques, Service des Forces Hydrauliques, Vol. 3, Paris, 1912, and Vol.
5, Paris, 1925; and Rapport sur les variations de longeur des glaciers de 1913
a 1928, Commission des glaciers, Union Ge"ode"sique et Geophysique Interna-
tionale, Venice, 1930. After 1925 there are sporadic measurements published in
Commission des glaciers, U.G.G.I. They are, however, sufficient to allow plotting
of the dashed part of the curve. The rapid recession of the last few years
parallels conditions in other parts of the Alps. The curve is plotted by O.
24 Plotted by the author from: D. B. Lawrence: Glacier Fluctuation for Six
Centuries in Southeastern Alaska and Its Relation to Solar Activity, Geogr. Rev.,
Vol. 40, 1950, pp. 191-223; idem: Glacier Fluctuation in Northwestern North
America during the Past Six Centuries. Proce's-Verbaux des seances de I' As-
semblee Gen. d'Oslo de I'Union Geodesique et Geophysique Internationale,
Louvain, 1948; and from H. W. Mathews: Historic and Prehistoric Fluctua-
tions of Alpine Glaciers in the Mount Garibaldi Map-Area, Southwestern
British Columbia, Journ. of GeoL, Vol. 59, 1951, pp. 357-380.
25 Ad. S. Jensen and B0rge Fristrup: Den arktiske klimaforandring og dens
betydning, sacrlig for Gr0nland, Geogr. Tidskrift, Vol. 50, 1950, pp. 20-47 (see
also W. R. B. Battle: Contributions to the Glaciology of North East Greenland
194849 in Tyrolerdal and on Clavering 0, Meddelelser om Gr0nland, Vol.
136, No. 2, 1952, pp. 1-26 (second section).
26 H. W:son Ahlmann: Studies in North-East Greenland, 1939-40, Part II,
Glacial Conditions in North-East Greenland in General and on Clavering
Island in Particular, Geografiska Annaler, Vol. 23, 1941, pp. 183-209. For
observations in 1947, see Ad. S. Jensen and B0rge Fristrup, op. cit. Charles
Swithinbank carried out investigations here during the Norwegian Polarbjorn
27 p. D. Baird: The Baffin Island Expedition, 1950, Geogr. Journ., Vol. 118,
1952, pp. 267-279.
28 See also Sigurdur Thorarinsson: Vatnajokull, Chapter XI, op. cit., and
"1 veldi Vatnajokuls," I in Lesb6k Morgunblathsins 1946, Reykjavik, 1946.
2 9 Rapport sur les variations de longeur de glaciers europ6ens de 1947 a 1950,
Union Geodesique et Geophysique Internationale, Assoc. Internatl. d'Hydro-
logie Sci., Assemblee Gen. de Bruxelles 1951, Vol. i, Louvain, 1952.
30 A review of these oscillations up to 1940 is given by F. E. Matthes, op. cit.;
A. E. Harrison: Ice Advance during the Recession of the Nisqually Glacier,
Mountaineer, Vol. 43, Dec., 1951, pp. 7-12.
31 D. B. Lawrence, op. cit.; J. L. Dyson: Glaciers of the American Rocky
Mountains, Triennial Report, Committee on Glaciers, Section of Hydrology,
American Geophysical Union (mimeographed), 1952. See also C. J. Heusser:
Pollen Profiles from Southeastern Alaska, Ecological Monographs, Vol. 22,
!952, pp- 33!-352-
32 W. O. Field, Jr.: Glacier Recession in Muir Inlet, Glacier Bay, Alaska,
Geogr. Rev., Vol. 37, 1947, pp. 369-399.
33 See also R. L. Nichols and M. M. Miller: The Moreno Glacier, Lago
Argentino, Patagonia, Journ. of Glaciol., Vol. 2, No. 11, 1952, pp. 41-50.
34 See also P. D. Baird: Report on the Northern American Glaciers, Union
Geodesique et Geophysique Internationale, Assoc. Internatl. d'Hydrologie Sci.,
Assemblee Gen. de Bruxelles 1951, Vol. i, Louvain, 1952. A. E. Harrison (per-
sonal communication) says that "the terrific recession characteristic of the
twenties and thirties seems to have passed a climax."
35 A. E. Harrison: Ice Advance, op. cit., and Glacier Studies 1952 Sequel,
Mountaineer, Vol. 44, 1952. In the latter he points out: 'In spite of two seasons
of excessive melting and the loss of ice at the higher elevations on the glacier,
the wave of ice reported last year (1951) is still making progress down the
Nisqually Glacier. The accumulation of ice since 1944 is too great to be dissi-
pated immediately." See also R. A. Dightman and M. E. Beatty: Recent
Montana Glacier and Climate Trends, Monthly Weather Rev., Vol. 80, 1952,
3<5Sigurdur Thorarinsson: Present Glacier Shrinkage, and Eustatic Changes
of Sea-Level, Geografiska Annaler, Vol. 22, 1940, pp. 131-159. See also, for
instance, L. C. W. Bonacina and E. L. Hawkes: Climatic Change and the
Retreat of Glaciers (with discussion), Quart. Journ. Royal Metcorol. Soc., Vol.
37, 19^7, pp. 85-95; R- F- Flin^ Climatic Implications of Glacier Research in
Compendium of Meteorology, edited by T. F. Malone (Amer. Meteorol. Soc.,
Boston, 1951), pp. 1019-1023.
37 J. de Heinzelin: Glacier Recession and Pcriglacial Phenomena in the
Ruwenzori Range (Belgian Congo), Journ. of Glaciol., Vol. 2, London, 1952,
pp. 137-140. (This issue also contains references to articles about other African
mountains which support glaciers.); E. Bergstrom: Som glaciolog p Ruvenzori
(As Glaciologist on Ruwenzori, with an English Summary), Ymer, Vol. 73, 1953,
38 Sirri Erinc.: Glacial Evidences of the Climatic Variations in Turkey, Geo-
grafiska Annaler, Vol. 34, 1952, pp. 89-98.
39 There is, however, "no proof of a general recession of south Patagonian
glaciers during the last twenty years" (Louis Lliboutry: More About Advancing
and Retreating Glaciers in Patagonia, Journ. of GlacioL, Vol. 2, No. 13, 1953,
pp. 168-172; reference on p. 172).
40 H. J. Harrington: Glacier Wasting and Retreat in the Southern Alps of
New Zealand, Journ. of GlacioL, Vol. 2, 1952, pp. 140-145.
41 Leo Lysgaard: Recent Climatic Fluctuations, Folia Geographica Danica,
Vol. 5, 1949 (with extensive bibliography); H. C. Willett: Temperature Trends
of the Past Century, Centenary Proc. Royal Meteorol. Soc., 1950, pp. 195-206.
Among numerous other studies of the present climatic fluctuation, the follow-
ing may be mentioned:
Anders Angstrom: Teleconnections of Climatic Changes in Present Time,
Geografiska Annaler, Vol. 17, 1935, pp. 242-258.
Idem: The Change of the Temperature Climate in Present Time, ibid, Vol.
21. 1939' PP- H9-13 1 -
Idem: Nederbordsklimatets andring i nuvarande tid, Stat. Mct.-Hydro. An-
stall, Meddelandcn, Serien uppsatscr, No. 37, Stockholm, 19 |i.
II. W:son Ahlmann: Den nutida klimatfluktuationen, Ymcr, Vol. 61, 191 1,
Idem: Den nutida klimatfluktuationen och Gronland, Del Gr0nlandske
Selskabs Aarsskrift, 1947, pp. 9-38.
Idem: The Present Climatic Fluctuation, Gcogr. Journ., Vol. 112, 1949, pp.
B. E. Eriksson: Till kannedomen orn den nutida klimatandringcn inom
omradena kring nordligaste Atlanten, Geografiska Annaler, Vol. 25, 1913, pp.
J6n Eythorsson: Temperature Variations in Iceland, Geograjnka Annaler,
Vol. 31, 1949, pp. 36-55.
Th. Hesselberg and B. J. Birkeland: Siikulare Schwankungen des Klimas von
Norwegen, Geofysiske Publikasjoner, Vol. 14, Nos. 4-6, Oslo, 1940-1913, and
Vol. 15, No. 2, 1944.
J. Keranen: Uber die Temperaturschwankungen in Finland und Nordcuropa
in den letzten hundert Jahren, Finn. Akad. der Wissensch., Sitiungsber., IQJI,
J. B. Kincer: Is Our Climate Changing? A Study of Long-Time Temperature
Trends, Monthly Weather Rev., Vol. 61, 1933, pp. 251-259.
Idem: Our Changing Climate, Trans. Amer. Geophys. Union, Vol. 27, 1946,
A. Labrijn: Het klimaat van Nederland gedurende de laatste twee en een
halve eeuw (With an English summary), Mededeling en Verhandelingen,
Koninkl. Nederl. Meteorol. Imt., Vol. 49, No. 102, Gravcnhage, 1945.
H. Landsberg: Climatic Trends in the Series of Temperature Observations
at New Haven, Conn., Geografiska Annaler, Vol. 31, 1949, pp. 125-132.
Idem: Some Recent Climatic Changes in Washington, D. C., Archiv fur
Meteorologie Geophysik und Bioklimatologie, Ser. B., Vol. 3, Vienna, 1951,
L. B. Leopold: Rainfall Frequency: An Aspect of Climatic Variation, Trans.
Amer. Geophys. Union, Vol. 32, 1951, pp. 347-357.
G. H. Liljcquist: The Severity of the Winters at Stockholm 1757-1942,
Geografuka Annaler, Vol. 25, 1943, pp. 81-101.
Idem: On Fluctuations of the Summer Mean Temperature in Sweden, ibid.,
Vol. 31, 1919, pp. 159-178.
Gordon Manlcy: Temperature Trend in Lancashire, 1753-1945, Quart, Journ.
Royal Meteorol. Soc., Vol. 72, 1946, pp. 1-31.
Idem: The Range of Variation of the British Climate, Geogr. Journ., Vol.
117, 1951, pp. 43-68.
Idem: The Mean Temperature of Cential England, 1698-1952, Quart. Journ.
Royal Meteorol. So( ., Vol. 79, 1953.
Idem: Climatic Variation, ibid., pp. 185-209. [Note the bibliographical
Sverre Petteisseu: Changes in the General Circulation Associated with the
Recent Climatic Variation. Gcografiska Annaler. Vol. 31, 1949, pp. 212-221.
F. Piohaska: /in Frage der Klimaandc-rung in Polar/one des Sudatlantiks,
Arcliiv fur Meteoiologie Gcophystk ujid Biokltmatologie, Ser. B., Vol. 3, Vienna,
'OS 1 - PP- 7-- 81 -
Mat tin Rodewald: Ruckgang dcr Klimaandeiung in den Vercinigtcn Staaten,
Geograjiska Annaler, Vol. 34. 1952, pp. 159-167.
E. Rubenstein: K piobleme i/minenija klimata, Ser. Hydjo-Meteorol. Serv-
ice. Sci. Research Dept., Geophys. Centre, Leningrad, 1946.
R Scherhag: Fine bemcrkenswertc Klimaandcrung uber Nordeuropa, An-
nalen der Hydrogr. und Alarit. Meteorol.. Vol. 64, 1936, pp. 96-100.
Idem: Die Fiwarinung des Nordlichcn Polargebiets, ibid.. Vol. 67, 1939, pp.
57- ( i7-
A. Wagner: Klimaandcrungen und Klimaschwankungcn, Die Wissenschaft,
Vol. 92, Brunswick, ig.jo.
H. Winter: Anderungen im Sommerklima scit 150 Jahren. Archiv fur
Mt'tcorologie Geophysik und Bioklitnatologie, Scr. B., Vol. 3, Vienna, 1951, pp.
^A. Labrijn: Ondcr/oek naar Klimaatschommelingcn in het Stroomgebied
van de Rijn, Mededeling van het Hedrijf der Gemeentewaterleidingen, No. 10,
De Watervoor/iening van Amsterdam, Aanvullende Gegevens op Rapport,
43 Mart in Rodewald, op. cit.
44 H. W:son Ahlmann: Glaciological Research, op. cit., pp. 77-78.
45 A. Wagner: Untersuchungrn der Schwankingcn der allgcmcine Zirkulation,
Geografiska Annaler, vol. 11. 1929, pp. 33-82.
46 B. E. Eriksson, op. cit.
47 H. W. Willctt: Descriptive Meteorology, New York, 1944; idem: Long-
period Fluctuations in the General Circulation of the Atmosphere, Journ. of
MeteoroL, Vol. 6, 19-19. pp. 34-50.
48 Sverre Pctterssen, Changes in the General Circulation, op. cit.
49 C. C. Walln: Recent Variations in the General Circulation As Related to
Glacier Retreat in Northern Scandinavia, Geofisica Pur a e Applicata, Vol. 18,
Milan, 1950, pp. 3-6; idem: Glacial- Meterological Investigations, op. cit.;
idem: Influences, op. cit.
so G. H. Liljequist: On Fluctuations of the Summer Mean Temperature,
51 Influences, op. cit.
52 D. F. Rex: Blocking Action in the Middle Troposphere and Its Effect Upon
Regional Climate, Tellus, Vol. 2, 1950, pp. 196-211 and 275-301; Vol. 3, 1951,
53 Sverre Petterssen: Some Aspects of the General Circulation of the Atmos-
phere, Centenary Proc. Royal Meteorol. Soc., 1950, pp. 120-155.
54 C. E. P. Brooks: Climate Through the Ages (rev. edit., London, 1949).
55 Ad. S. Jensen and B0rge Fristrup: Den Arktiske klimaforandring, op. cit.
56 Hans Hedtoft: Gr0nlands Fremtid, Det Gr0nlandske Selskabs Aarsskrift,
1949, pp. 22-42. In a lecture at Oslo in February, 1953, Director P. Rosendahl
of the Greenland State Department in Copenhagen pointed out that the
principal reason for the new era in Greenland has been the present climatic
fluctuation with the associated disappearance of the seals and the northern
migration of cod.
57 H. W:son Ahlmann: The Present Climatic Fluctuation, op. cit., p. 192.
58 The Recent Climatic Fluctuation in Finland and Its Consequences, Fennia,
Vol. 75, Helsinki, 1952.
59 In an unpublished article C. C. Wallen has shown that from the period
18831913 to 1930-50 the temperature of the surface water in the Gulf of
Bothnia rose as much as 2 C. in August, and little less in other months. A
warming up of the water has also taken place in the southern part of the
Baltic as well as on the west coast of Sweden.
60 G. Sandberg: Den pagaende klimatforandringen, Svenska Vall-och Mosskul-
turforeningens Kvartalsskrift 1940, Uppsala, 1940; and his report to the author
dated July, 1952.
61 F. Bergsten: Contribution to Study of Evaporation in Sweden, Sveriges
Meteorol. o. Hydrol. Inst., Meddelanden Ser. D., Nr. 3, 1950.
62 S. Ve: Stig skoggrensa? Tidskrift for Skobruk, No. 9, Oslo, 1951, pp. 305-
63 Sigurdur Thorarinsson: Notes on Patterned Ground in Iceland, with
Particular Reference to the Icelandic "Flas," Geografiska Annaler, Vol. 33, 1951,
pp. 144-15 6 -
6 4 R. F. Black and W. L. Barksdale: Oriented Lakes of Northern Alaska,
Journ. of GeoL, Vol. 57, 1949, pp. 105-1 18.
6 5 Finnur Gudmundsson: The Effect of the Recent Climatic Changes on the
Bird Life of Iceland, Proc. loth Internatl. Ornithological Congress, Uppsala
1950, Stockholm, 1951, pp. 502-514.
66 Plotted by E. Bergstrom. Before 1650 A.D. based principally on: F.A.D.
Enquist: Die glaciale Entwicklungsgeschichte Nordwestskandinaviens, Sveriges
GeoL Undersokning, Ser. C., Nr. 285, 1918. After 1650 A.D. on: Knut Faegri:
On the Variations of Western Norwegian Glaciers During the Last 200 Years,
Proces-Verbaux des seances de I'Assemblee Gen. d'Oslo de ['Union Geodesique et
Geophysique Internationale, Louvain, 1948; Axel Hamburg: Sarjekfj alien,
Yrner, Vol. 21, 1901, pp. 145-204 and 223-276; N. H. Magnusson, E. Granlund,
and G. Lundqvist: Sveriges geologi, 1949; A. Wagner: Klimaiinderungen und
Klimaschwankungen, op. cit.; A. Walle"n: Om langvariga klimatforandringar
och kallorna for deras utforskande, Popular Naturvetenskaplig Revy, Vol. 6,
Stockholm, 1918; Anders Angstrom: Sveriges kliinat, Generalstabens litografiska
6 7 Plotted by O. Licstol, Oslo. Bases: J. B. Rekstad: Skoggnensens og sneliniens
st0rrc h0itle tidligere i det sydlige Norge, Norges Geologiske Under so gelse,
Aarbog for 1903, Vol. 36, No. 5; Knut Faegri: Ober die Langenvariationen
einigcr Glctschcr dcs Jostedalsbre, Bergens Museums Arbok 1933, Naturviden-
skapelig rekke, No. 7; idem: Quartargeologische Untersuchungen im westlichen
Norwegen, I-II, Bergens Museums Arbok, Heft 3, No. 8, 1935, and Heft 2,
No. 7, 1910; Erik Granlund: De svcnska hogmossarnas geologi, Sveriges Geol.
Unders. Ser. C., No. 373, Arsbok, Vol. 26, No. i, 1932.
68 Jon Eythorsson: Tliykkt Vatnajokuls, Jokull, Joklarannsoknafelag Islands,
Vol. i, Reykjavik, 1951.
<*>> Sigurdur Thorarinsson: The Thousand Years' Struggle Against Ice and
Fire (Special University Lecture, Bedford College, London University, February,
7<> H. W:son Ahlmann: The Present Climatic Fluctuation, op. cit., p. 166.
P. N0rlund: De gamle Nordbobygder vcd Vcrdcns Ende, Copenhagen, 1934;
J. Iverscn: Nordboernes Undergang paa Gr0nland i geologisk Belysning, Gron-
landske Selskabs Aarsskrift, 1034-35, 1935.
71 P. N0ilund: Buried Norsemen at Herjolfsnes: An Archeological and
Historical Study, Meddelelser om Gr0nland, Vol. 67, 1924, pp. 1-270 (see the
abstract by William Hovgaard: The Norsemen in Greenland, Geogr. Rev., Vol.
15, 1925, pp. 605-616); Lauge Koch: The East Greenland Ice, Meddelelser om
Gr0nland,Vo\. 130, 1915.
72 H. W:son Ahlmann: The Present Climatic Fluctuation, op. cit., p. 166
73 H. Kinzl: Die grossten nacheiszeitlichen Gletschervorstosse in den Schweizer
Alpcn und in der Mont Blanc-Gruppc, Zeitschrift flir Gletscherkunde, Vol. 20,
JOS 2 ' PP- 269-397.
74 F. E. Matthes: Glaciers, op. cit., p. 207.
75 Sigurdur Thorarinsson: Some Tephrochronological Contributions to the
Volcanology and Glaciology of Iceland, Geografiska Annaler, Vol. 31, 1949, pp.
239-256. See also E. M. Todtmann: Im Gletscherruckzugsgebiet des Vatna
Jokull auf Island, Neues Jahrb. Geol. und Palciontologie, Nov. 1951, Stuttgart,
95 l -
76 H. W:son Ahlmann: Glaciers in Jotunheim and their Physiography,
Geografiska Annaler, Vol. 4, 1922, pp. 1-57.
77 Leo Aario: Ein nachwarmezeitlicher Gletschervorstosse in Oberfernau in
den Stubaier Alpen, Acta Geographica, Vol. 9, No. 2, Helsinki, 1944, pp. 1-31.